Glowlamp



April 10, 1934. s F MARVIN ET AL 1,954,420

GLOWLAMP Filed May 8, 1951 Patented APL-10, 1934 RATENr OFFICEGLOWLAIVIP Stuart vF. Marvin, Nutley, N. J., and Philip J. Kayatt, NewYork, N. Y., assignors to Radio Inventions, Inc., New York, N. Y., acorporation o! New York Application Mayv 8, 1931, Serial No. 535,933

Claims. (Cl. 176-122) The present invention relates to gaseous glowlamps for television apparatus and the like.

More specificallythis invention relates to gaseous glow lamps whereinthe useful optical output 5 is obtained in a concentrated beam orat apoint of restricted area. Y

This invention relates particularly to the construction, form, size andmode of operation of such gaseous glow lamps used as a light sourcevariable in accordance with changes of the electric exciting currentapplied thereto.

One object of this invention is the production of a concentrated beam oflight capable of rapid fluctuation in intensity and of being directed,focused or otherwise acted upon by optical means. I Another object isthe .provision of a small, rugged and compact television lamp suitablefor commercial production and use.

Another object of our invention is to produce a concentrated beam at aposition where it can be readily projected through a transparent portionof the walls of an outside vessel with the minimum of lopticaldistortion due to the character of these Walls at that point and theirpresence in the path of this beam.

. A further object is the production of a lamp operable on electricalpotentials and currents not exceeding the `values usual in televisionreceivers.

A further object is to coniine the greater part of light production in atube of the gaseous glow type, to the neighborhood of'the electrodesthemselves, and to reduce to a minimum degree the .diiiusion of suchglow throughout the entire gas containing chamber of such tube.

Other objects and uses of our invention will be apparent from theaccompanying drawing.

Fig. 1 is a view partly in cross section of one form of our invention.'

Fig. 2 is an alternative form of one detail of our invention.

In Fig. 1, 1 represents a chamber of insulating material, such asisolantite or the like, which is capable of ready degasication and ofwithstanding the moderate elevation of temperature which may be producedtherein during operation. I have found a suitable size of such tube tobe of an inch in external diameter, with an in terior diameter of ,3g ofan inch.

2 represents an electrode which is situated within one end of thisinsulating chamber. Ihis electrode may be either solid or of a hollow orcup like formation. The solid electrode shown in the drawing mayconveniently be slightly spaced from the interior Wall of the insulatingchamber. In case that a hollow electrode isjemployed we prefer that theelectrode :lit snugly against this wall, but the degree of approximationof the eiectrode and chamber wall may be varied although we prefer thatthe distance do not exceed tnat corresponding to the minimum ionizationpotential. The lateral position relative Vto the insalator may beadjusted to secure the optimum shape and size of glow produced:

, 3 represents the other electrode of our tube, shaped in the-form of acylinder which may snugly embrace the exterior wall of chamber 1. Theopen end of this electrode may extend approximately 1/4 beyond the endof the insulator, although such extension is not essential and it may beflush with, or notfreach the end of the insulator.

4 represents insulating sleeves which serve partially to support theinsulating chamber and electrodes hereinbefore described and also tocover adequately the lead Wires 5 which convey cur- 75 rent to theelectrodes of our invention, and pass `at their other end through thepress 6 to the exterior of the tube.

7 represents the usual exhaust tubulature which furnishes means for theexhaustion and lling of so such a tube, and which is sealed ol at itsextremity at the conclusion of the manufacture of the tube. A

8 represents a constriction 'in the size of the interior of insulatingchamber 1 at the end which 35 comes within the hollow electrode 3.

9 indicates a tube base of the usual type having prongs 10 to whichleads 5 are connected.

Fig. 2 shows an insulating chamber 1 not employing such constrictionwhich latter need be employed only when it is desired to concentrate theglow discharge to an area of smaller cross section than that ofelectrode 2.

4Insulating sleeves 4 and chamber 1 serve, to keep unwanted dischargesfrom occurring along the length of the lead Wires conveying current tothe electrodes. It is preferred that such insulating sleeves 4 be rmlyfastened and protected by such means as insulating cement at the pointswhere they make contact with the walls of chamber l, and/or of electrode3. V

One or both of the electrodes of our-invention may be either made of, orcoated with such materials as minimize the potentials necessary toinitiate and/or maintain discharges in such luminescent gaseous tubes.Such materials are the alkali metals, alkali-earth oxides, magnesium,aluminum or other well known like substances.

The electrode structures and insulating chamber of our device aresupported by lead wires 5 110 and the insulating tubes 4 surrounding thesame. These tubes may be firmly fastened to the press 6 by any suitablemeans, such as projections upon the press which are to t within orenclose the vexterior of tubes 4 for a short distance, or insulatingcement may be used to make such connections. These connections should beof a gas tight nature under usual circumstances, further to avoidunwanted discharges at such places.

With the form and size of structure herein described we make theinterior electrode 2 the cathode and the exterior electrode 3 the anode,in order that the discharge without the chamber 1 be substantially ofthe dark space type and the visible glow be conned substantially withinthe chamber 1.

During the operation of our invention both the electrode thereof aremaintained at a temperature substantially below incandescence. Thestructures of our invention hereinbefore described are completelyimmersed within an atmosphere of some ionizable gas such as monatomicgases of the inert group, mercury or the like. Gases commonly employedare neon, helium, nitrogen or argon. Such gases may be employed eitherin varying degrees of purity or in intentional admixtures, according tothe character of the luminous output desired. It is well known that byproper selection of these gases such luminous output may be made tooccupy various portions of the visible and invisible spectrum.

In order to maintain such a gaseous atmosphere around the structures ofour invention, they may be suitably enclosed within a protecting andconfining membrane in the shape of a vessel indicated at 11. Such amembrane may be entirely transparent or translucent. 0n the other hand,it is possible with our invention to construct such a vessel with wallsopaque at all points except those adjacent to the luminous beamprojected from the interior or insulating chamber 1 through electrode 3.It is also possible to use a completely transparent vessel which isenclosed by an outer protective and opaque coating, such as a metallicshield, at all points except the one through which the light is to betransmitted. This mechanical and/or electrical protection of ourinvention constitutes a feature of great commercial importance.

For convenience in handling and connecting it is preferable that astructure according to our invention be mounted at its lower extremityin some base as shown at 9, which is of the type customarily employedwith thermionic vacuum tubes. In this case the leads 5 may terminate intwo .only of the contact pins in such base.

By manufacturing these tubes with uniform size of interior parts, andwith such parts uniformly located with respect to the pins of themountingbase, one tube may be rapidly and easily replaced by anothersimilar tube, in case of failure. Such rapid replacement can be made ina minimum of time, and will not necessitate extensive readjustment ofany optical systems employed exteriorly to the tube.

While we have mentioned certain specific sizes of the parts of ourstructure, such sizes are purely illustrative, and we do not in any wayrestrict our invention to such sizes or ratio of sizes.

While we do not confine ourselves to any specific pressure of thegaseous atmosphere within our tube, we have found that when neon isemployed a pressure of 6 to 12 mm. of mercury is very suitable, althougha suitable discharge may be obtained at pressures ranging from 2 to 20mm.

With such sizes of apparatus as given, a suitable potential is found tobe from 200 to 400 volts with a current of 15 to 50 milliamperes.

With suitable arrangement and sizes of parts, selection of gas andpressure, this invention may operate on substantially lower voltages, ofthe order of 100 volts. Likewise, with appropriate design and gasfilling, this invention can be embodied in a form capable of employingvoltages between 500 and 1000, or even higher. In this last case, it maybe desirable to employ a base larger, or of different type than theordinary radio tube base herein described.

We have found it desirable to ascertain the optimum operating pressureof gas within our tube by connecting thereunto a source of currentsupply, while the tube is still connected to the gas supply employed forfilling the same and before tube '1 is finally sealed oil, and adjustingthe gas pressure until the desired concentrated glow is had at the ratedoperating voltage and current.

One advantage of our invention is that a large volume of gas may beenclosed within the outer membrane 9, which may in this fashion beconsidered to function as a gas reservoir, enclosing a discharge chamberof smaller dimensions. Since it is well known that the gas pressure in adischarge tube of small volume tends to change during life, it can beseen that the tube of our invention having effectively a large reservoirof gas in the discharge path will have a long useful life.

Another advantage of our structure is that a beam of light may beproduced which is of substantially uniform brightness throughout itscross section.

A further advantage is that a concentrated beam is produced such as canbe readily manipulated by means of optical devices such as lenses,mirrors and the like. 'Ihe action of such optical devices was ineicientwhen exerted upon the diffused radiance of previous forms of glow tube.They may be made, however, highly eflcient when employed in connectionwith a concentrated glow of our invention.

Another advantage is that the concentrated beam is produced adjacent apoint of the outer gas containing vessel which is easily made thin anduniform in its optical character.

Furthermore the outside envelop of our invention mayr be made opaque atall points except those immediately adjacent to the hollow electrodethereof, which permits, when desired, the suppression of unwanted lightbeams which otherwise might emanate therefrom.

Another advantage of our invention is that when the desired light isproduced in the ultraviolet portionof the spectrum, it is possible toutilize a window of quartz or similar material of a moderately smallsize', which is advantageous in View of the high cost of such materials.Furthermore such a window employed with light in the visible spectrumwill allow the production of light of great intensity, even thoughconsiderable heat production is thereby entailed.

Other changes in the parts and dimensions of our invention can bereadily made by one skilled in the art, in `order to adapt it to specialpurposes, and we do not limit ourselves to such special forms or sizesas have been hereinbefore set forth, except in as far as they arelimited by the claims hereunto appended.

vWe claim:

1. A gaseous glow lamp comprising an outer chamber translucent at leastin part, an opaque insulating cylinder of material having high thermalcapacity and resistance having enclosed in one end an electrodesubstantially in contact with the inner wall thereof and directlyvisible through the open end thereof, a hollow ring shaped electrodeembracing at least partially the other end of said cylinder, connectingand supporting means for said cylinder and electrodes, said cylinderbeing so positioned that its open end is adjacent a lateral wall of saidouter chamber, said chamber being lled with a gas glowing underelectrical excitation, and said connecting and supporting means beingmechanically and electrically shielded from said gas, so that theglowing gas discharge is conned to the electrodes proper.

2. A gaseous glow lamp including an outer gas containing chamber, aninner glow chamber, said inner chamber having its axis substantially atright angles to the axis of thelouter chamber and communicating with theouter chamber through an orifice of constricted area, compared with thearea of the inner chamber, a hollow electrode positioned within saidouter gas chamber surrounding at least a portion of said inner glowchamber and another electrode positioned within said inner glow chamberbut having at least a portion-thereof visible through said orice andsaid hollow electrode.

3. A television spot-source light including a transparent tube having are-entrant stern, conducting lead wires sealed in said stem andsupported thereby, insulatingmaterial covering said lead wires,substantially co-axial discharge electrodes supported by and connectedto said lead wires. the larger electrode being hollow. an annularinsulator of opaque material having high thermal conductivity andresistance between said electrodes and deriving its sole support throughthe lead wires, said insulator having an opening along its axis so thatthe smaller of said electrodes is visible through the larger electrodeand through said opening. f

4. A television reproducing lamp including an opaque insulatingdischarge chamber of material having high thermal capacity andresistance, one electrode within said chamber, another electrode atleast partially embracing the exterior wall of said chamber andextending beyond the end of said chamber, so that the luminous dischargewithin said chamber can be viewed through said second electrode,insulated leads to said electrodes, supporting said insulating dischargechamber substantially at right angles to the axis of the lamp, an outertransparent chamber containing said discharge chamber and saidelectrodes, and an inert gas lling said outer chamber.

5. A gaseous glow lamp including an outer gas containing chamber, aninner glow chamber, said inner chamber having its axis substantially atright angles to the axis ofthe outer chamber, a hollow electrodepositioned within said outer gas chamber surrounding at least a portionof said inner glow chamber and another electrode positioned within saidinner glow chamber but having at least a portion thereof visible throughsaid hollow electrode.

STUART F. MARVIN. PHILIP J. KAYATT.

